1. Field
Exemplary embodiments of the present invention relate to a memory system.
2. Description of the Related Art
In the early stage of a semiconductor memory device industry, there were many originally good dies on the wafers, which means that memory chips were produced with no defective memory cells through a semiconductor fabrication process. However, as the capacity of memory devices increases, it becomes difficult to fabricate a memory device that does not have any defective memory cells, and nowadays, it may be said that there is substantially no chance that a memory device is fabricated without any defective memory cells.
To address such limitations, a repair method is used which includes adding redundancy memory cells in a memory device and replacing any defective memory cells with the redundancy memory cells.
Another solution employs an error correction circuit (ECC) for correcting errors in a memory system. Typically, an ECC may correct an error that occurs because of a defective memory cell and also an error that occurs in the transmission of data in a read or a write operation of a memory system.